The Reaper is back but unlike Persona 5 this ultimate boss is only available after certain requirements are met. Here’s how to unlock the Reaper. After beating the game Lavenza will inform Joker about a great threat and tell ask you to beat the Monarchs again. These Plus battles are only unlocked after beating them the second time. The third fight with these bosses is the ultimate challenge so bring your A-game. After beating the Monarchs again you’ll unlock the Reaper in the Cage of Desolation with a green marker. Be prepared, this monster is no joke.